Thermal timer for toasters



Feb. 24, 1948. WALDER ET AL 2,436,735

THERMAL TIMER FOR TOASTERS Filed March 14, 1941 6 Sheets-Sheet l Feb.24, E WALDER ET AL THERMAL TIMER FOR TOASTERS Filed March 14, 1941 6Sheets-Sheet 2 Feb. 24, E A ER ET AL THERMAL TIMER FOR TOASTERS FiledMarch 14, 1941 6 SheetS Sheet 3 Feb. 24, 1948. WALDER ET AL 2,436,735

THERMAL TIMER FOR TOASTERS Filed March 14, 1941 6 Sheets-Sheet 5 E.WALDER ET AL THERMAL TIMER FOR TOASTERS Filed Ma rch 14, 1941 6Sheets-Sheet 6 Jay-1a:

O 57 7! 4 Q 73 I "69 I d Emil alda- Patented Feb. 24, 1948 2.430.135-maamar. 'rnvma ron rons'rnas Emil Walder and Joseph w. Myers,Philadelphia, Pl... assignors, by meme assignments, to Proctor ElectricCompany, Philadelphia, Pat, a corporation of Pennsylv Application March14, 1941, serial No. 383.400

This invention relates to automatic electrical devices and, moreparticularly, to a novel automatic bread toaster, and has for itsprincipal object to provide an improved device of this general characterembodying novel means for timing its operation.

A more specific object or the invention is to provide an improved deviceof this character whose operation is automatically terminated after adetermined time interval.

Another object of the invention is to providea novel device whoseoperation is controlled by a thermal-timing mechanism comprising athermal-responsive element arranged for alternate and repeated heatingand cooling to control the said mechanism.

A further object of the invention is to provide a novel device whoseoperation is controlled by a member movable to a position at which itterminates said operation, and the movement of said member to saidposition is timed by the alternate and repeated heating and cooling ofa, thermal-responsive element.

A further object of the invention is to provide a novel device oi thischaracter wherein the thermal-responsive element is arranged to movebetween a pair of spaced detents .or stops in response to the heatingand cooling action.

Still another object of the invention is to provide an adjustableheating means for the thermal-responsive element whereby the. period ofheating the said element may be varied to thereby vary the timing actionof the control mechanism and thus vary the time of operation or thedevice being controlled.

A further object of the invention is to provide a. novel timingmechanism for controlling the operation of an electrical device, such asa bread toaster.

While the invention is particularly directed to automatic toasters, andsuch adaptation is illustrated in the drawings and will be particularlydescribed, it will be obvious that the invention is applicable to otheruses.

In the accompanying drawings:

Fig. 1 is a perspective view of a toaster embodying the invention;

Fig. 2 is an end view of the toaster with the cover shown only inoutline and with the parts in inoperative position;

Fig. 3 is a fragmentary view of the device taken from the right-handside of Fig. 2 along line 3-3;

Fig. 4 is an end view of the device similar to pre-\ 4 Claims. (Cl.161-1l 2 Fig. 2 but showing the parts in operative position;

Fig. 5 is a fragmentary view taken from the right-hand side of Fig. 4along line 5-5;

Fig. 6 is an elevational view or the opposite end of the toaster showingthe thermal-timin mechanism with the parts in inoperative position;

Fig. 7 is a partial side view taken from the 0 left-hand side of Fig. 6;

' operation of the mechanism;

Fig. 14 is a plan view of the thermostatic control device;

Fig. 15 is an enlarged detail view taken along line l5--| 5 of Fig. 9and illustrating certain parts of the timing mechanism; and

Fig. 16 is a detail view of the adjustable heater for the thermostaticcontrol element of the timing mechanism.

Referring to Fig. 1, there is shown a toaster oi. the two-well typedesignated generally by reference character I, the bread wells beingshown at 2 and 3. The controls extend from one end of the device asillustrated. At 4, there is shown a depressible knob, by means of whichthe bread carriage is moved to its toasting position and the toastingoperation is initiated. At 5, there is shown a depressible knob by meansof which the latch for the bread carriage may be released at will.Normally, this knob will not be utilized since the toaster will functionautomatically by means of the mechanism hereinafter described. At 8,there is shown a rotatable knob by means of which the toaster isadjusted to effect different degrees of toasting of the bread.

The interior well structure or the toaster, including the heatingelements arranged in cooperative relation with the well spaces, has notbeen illustrated since it forms no part or the pres ent invention. Theinterior structure may be of any suitable form, such as employed incommercial toasters of this general type having a movable bread carriageto support the bread slices.

Referring now to Figs. 2 to 5, the framework of the toaster includes atop member I, a bottom or base plate 8, and an end plate 9 with whichthe mechanism now to be described is associated. The end plate 9 is atthe end of the toaster adiacent the control knobs. The bread carriageincludes as a part thereof a plate In which is slidable along a verticalsupport and guide post The knob 4, previously mentioned, is carried byan extension |2 turned out from the body of plate l0. A spring l3 hasits lower end secured to an extension l4on plate l while the upper endof the spring is anchored to the top plate.

1 at l5. This spring urges the bread carriage upward to its dischargeposition, as shown in Figs. 2 and 3. By means of knob 4, the carriagemay be moved downward against the action of spring l3 to its toastingposition, as shown in Figs. 4 and 5. The carriage is held in itstoasting position by means of'a pivoted latch IS, the hooked end ll ofwhich is adapted to engage a cooperating latch element |8 extending fromthe plate I 0, as shown in Figs. 4 and 5. The latch II is urged towardlatching position by a leaf spring Ilia mounted on base plate 8. Whenthe latch I6 is tripped either manually or automatically, the breadcarriage rises to its bread-discharge position under the action ofspring i3.

Preferably. a dashpot I9 is employed to retard the upward motion of thebread carriage. The dashpot may comprise a hollow cylinder mounted onthe base plate 8 and a piston 20 (see Fig. 2) whose rod or stem 2| isattached to the plate "3 The electrical circuit of the toaster iscontrolled by a switch which is operated by the bread carriage. Thisswitch comprises a stationarycontart 22 mounted on the base plate 8 andinsulated therefrom, and a movable contact element 23 carried by aresilient arm 24 which is mounted upon an insulating terminal block 25secured to the end plate 9. A finger 26 is turned out from the resilientarm 24 and is adapted to be engaged by a disk 21 carried by an arm 28formed on the plate ID. The disk 21 is formed of insulating material.When the parts are in inoperative position, as shown in Fig. 2, thecontacts 22 and 23 are maintained open by the resilience of arm 24. Whenthe bread carriage is lowered by means of knob 4 to init ate thetoasting operation, disk 21 engages arm 26, thereby causing contact 23to engage contact 22. When the toasting operation is terminated and thebread carriage moves to its upper position, the switch elements 22 and23 are opened.

The details of construction of the bread carriage other than those abovedescribed form no part of the invention and may take the usual formfound in prior toasters of this general type.

Returning now to the latch member l6, this member has a projecting arm29 on whi h 'the knob 5 is mounted and it also has a projecting arm 30by means of which the latch member is adapted to be operated. The arm 30extends through a slotted tripping arm 3| whose upper endis pivotallyattached to an assoc ated arm 32. The arm 30 has a notch 33 cut thereinto accommodate the lower portion of arm 3| with which the arm 30 is thusinterlo kingly engaged. The arm 32 is attached to one end of a rod orshaft 34 which extends lengthwise of the toaster along one side thereofand is rotatably carried by support elements secured to the framework ofthe toaster. One such element is shown at 35.

The arm 32 carries a pivoted member 36 which is adapted to be engaged bya roller 31 carried by the projection l4 of plate ill (see Figs. 2 and 3The member 36 is normally held against a stop 38 on arm 32 by a spring33 also carried by arm 32. When the bread carriage is lowered toinitiatethe toasting operation, the roller 31 engages the end of member36 and rotates the arm 32 counter-clockwise, as viewed in Fig. 2. Thislowers the latch-tripping arm 8| from its tripping position of Figs. 2'and 3 to its inoperative position of Figs. 4 and 5. The rotation of arm32 eifectsrotation of shaft 34 to thereby set the timing mechanism foroperation, as will be presently described. The latch member it engagesthe associated latch element It and holds the bread carriage in itstoasting position. The timing mechanism to be described hereinaftereffects a gradual rotation of shaft 34 in a direction to raisethelatch-tripping arm 3| until it finally reaches its tripping position, atwhich time the latch member I6 is actuated, thereby releasing the breadcarriage. As, the roller 31 is carried upward, it deflects the pivotedmember 36 from its path, the pivotal mounting of the latter permittingthis without affecting arm 32.

Referring now to Figs. 6 to 9, the thermaltiming mechanism provided bythis invention and which controls the operation of the latch-trippingarm 3| is disposed at the opposite end of the toaster adjacent the endplate 40 of the-toaster framework. The timing mechanism is supported bya plate 4| secured to the end plate 40. As shown in Fig. 7, therotatable shaft 34 is supported at one end by the plate 4|. An arm 42 isattached at one end to the rotatable shaft 34 and at its free end thisarm has an arcuate extension 43 with gear teeth 44 thereon, thusproviding a gear sector. The arm 42 is urged counter-clockwise, asviewed in Figs. 6 and 8, by a spring 45 coiled about the end of rod 34and having'one end anchored by an extending ing 46 on plate 4|, whilethe opposite end of the spring engages a turned lug 4'! on arm 42. Thegear sector 43 meshes with a small pinion 48 which is loosely carried bya pin 49 rotatably mounted on the plate 4|. A ratchet wheel 50 isfixedly mounted on pin 43 adjacent pinion 48 and pivotally carries apawl 5| (see Fig. 15) which engages the pinion 48. A spring 52 issecured to a small pin 53 on ratchet wheel 50, and the free end of thesprin is seated in a slot in pawl 5|. as shown at 54, and serves tomaintain the pawl in engagement with the pinion 48. A pawl 55 (see Figs.6 and 8) is pivotally mounted on plate 4| at 56 and is so arranged thatit is urged by gravity into engagement with the ratchet wheel 50. Thispawl and the associated ratchet wheel are so designed that the ratchetwheel is permitted to move clockwise, as viewed in Figs. 6 and 8, but isprevented from moving counter-clockwise.

A crank wheel 51 is also fixedly mounted on pin 49 adja ent the ratchetwheel 50, as shown in Figs. 7 and 9. A link 58 is connected between thecrank wheel 51 and one end of a rocker arm 59 which is pivotally mountedon a post carried by the plate 4|. The opposite end of the arm 59carries a bimetallic strip 6| which constitutes a thermostatic element.The free end of strip BI is arranged to cooperate with upper and lowerspa ed stops B2 and 63 carried by a bracket 54 secured to the plate 4|.The stops may be formed as integral parts of a resilient sheet which isbent and cut to form the desired arrangement of the stops, asillustrated in Figs. 10 to 14. It will be noted that the effectiveportions of the stops 62 and 63 are arranged in horizontally offset somerelation with respect to one another for a purpose which will beapparent later.

Adjacent the thermostatic strip .8l,-there is provided an electricalheater element 55 which is included in the electrical circuit of thetoaster. This heating element is carried by a bracket 85 (see Fig. 16)which is adiustably carried at the end of an adjustable arm 61. A heatreflector 65a is also mounted on bracket 55 adjacent the heater. Theadjustable mounting of bracket 68 on arm 61 maytake the form of a simpleslot and screw mounting 58. The arm 61 is pivotally attached to plate 4|at 69. This arm has a pair of turned-put flanges l and II between whichthere is disposed a cam I2 mounted on the end of a rotatable shaft 18which extends lengthwise of the toaster and is Journaled in plates 8 and4!. The opposite end of the shaft 18 carries the knob 5 previouslyreferred to. By rotating this knob and thereby rotating the cam 12, thearm 41 may be rotated slightly to vary the position of the heaterelement 65 with respect to the thermostatic strip SL The purpose of thiswill be fully understood later.

When the thermostatic strip M is cold, its end is aligned with theeffective portion of the upper stop 62, as shown in the solid-lineillustration of r Fig. 14. When the thermostatic strip is heated by theheater 85, it flexes outward to the brokenline position of Fig. 14 sothat the end of the strip is no longer aligned with the upper stop 52but is then aligned with the effective portion of the lower stop 53. Theoperation of the timing mechanism and the control thereof by thethermostatic element and its associated stops may be clearly understoodby considering the operation of the toaster as a whole.

When the toaster is cold and the parts thereof are in inoperativeposition, the various elements are disposed as shown in Figs. 2, 3, 6and 7. At this time, the arm 42, which carries the gear sector 43. isdisposed in its uppermost position and is thus maintained by itsassociated spring 45, while the latch-tripping arm 3| at the op-. positeend of the toaster is likewise disposed in its uppermost or trippingposition. When it is desired to operate the toaster, the knob 4 isdepressed, thereby lowering the bread carriage and effecting closure ofthe switch 22-23, as above described. During this lowering movement ofthe bread carriage, the roller 31 engages member 38 to lower thelatch-tripping arm 3| and at the same time lower the arm 42 through themedium of the rotatable rod or shaft 34- The parts are then in thepositions shown in Figs. 4, 5, 8 and 9. During the lowering of arm 42,the gear sector 43 rotates the pinion 48 while the associated partsremain stationary, and the pawl 5| simply rides over the teeth of thepinion. This rotation of the pinion 48 is clockwise as viewed in Fig.15, and it will be seen that the pawl 5| permits such rotation of thepinion relativeto the ratchet wheel 50 which is held against rotation bypawl 55. However, the pawl 5| prevents free rotation of the pinion 48 inthe opposite direction and serves to interlock the pinion with theratchet wheel and hence with the crank wheel 51. Due to thisinterlocking of these parts and due to the engagement of thethermostatic element 5| with the stop 52, the arm 42 is held in itslowermost position, and, consequently, the latch-tripping arm 3| is heldin its lowermost position.

Initially, therefore, the parts of the thermaltiming mechanism aredisposed as shown in Fig. 8. At this time, the thermostatic element Siis cold and its free end is aligned with the upper stop 82 which servesto retain the parts in the condition of Fig. 8. It will be noted thatthe link 58 and the crank wheel 51 are slightly removed from dead centerposition. The heater element 65, being disposed adJacent thethermostatic strip 6| in its uppermost position, effects a gradualheating of the thermostatic element causing it to flex outward, as shownin Fig. 14 until the end of the thermostatic element frees itself fromthe stop 52. This permits the arm 42 to rotate counter-clockwise, asviewed in Fig. 8, under the influence'of spring 45 and, at the sametime, the pinion 48 and ratchet wheel 50 rotate clockwise(counterclockwise in Fig. 15). The initial movement causes the armstructure 58 to rock slightly in a clockwise direction about its pivotalmounting 50, thereby causing the end of the thermostatic strip 5| torise slightly above the level of stop 82, as indicated by theillustrations of Figs. 10 and 12. However, when the link 58 and crankwheel 51 reach dead center position, the arm structure 58 is rocked inthe opposite direction and, since the end of the heated thermostaticstrip ii is now aligned with the lower stop 63, as shown in Fig. 14, thedownward movement of the thermostatic element is interrupted when itsend abuts against the lower stop, as shown in Figs. 11 and 13. At thistime, the movement of the arm 42 is interrupted in the position of Fig.11. Thus, the arm 42 has been moved through a certain increment and thelatch-tripping member 3| has been moved upward accordingly.

The thermostatic strip 6i now commences to cool and returns to its innerposition. When it has moved sufficiently to release its end from thelower stop 63, the arm 42 is again permitted to rotatecounter-clockwise, as viewed in Figs. 8, 10 and 11. Since the link 58and the crank wheel 51 were slightly ofi dead center position, as shownin Fig. 11, the initial movement of the parts causes the arm structure59 to rock slightly counter-clockwise about its pivotal mounting 60causing the end of the thermostati element to move below the level ofstop 63, as shown in the broken-line representation of Fig. 13. However,when the link 58 and the crank wheel 51 reach dead center'position, thearm structure 59 is rocked clockwise and, since the end of thethermostatic element is now aligned with the upper stop 62, the movementof arm 42 is interrupted when the said end engages the upper stop. Thus,the arm 42 and the latch-tripping member 3| have been moved through afurther increment.

The thermostatic element being again positioned in proximity to theheater element 65 commences to heat and the cycle is repeated. Thiscyclic action continues until the latch-tripping member 3| has movedupward sufliciently to trip the latch l8 and release the bread carriage.thereby interrupting the toasting operation.

Thus, it will be seen that the toasting operation is controlled by athermal-timing mechanism which is conditioned for operation when 60, andsuch movement is eflected by the mechanism as the arm 42 and trippingmember move upward, and the rocking movement is controlled by the stopsand the heater so as to control the movement 01 the tripping membertoward its tripping position.

It is important to note that the thermostatically-controlled timingmechanism controls the toasting operation according to the general heatcondition of the toaster. When the toaster is cold, it takes longer forthe toasting of a bread slice to a given degree than it does when thetoaster is heated to its normal operating temperature. Since thethermostatic control element is subjected to the general heat of thetoaster and follows the heat condition of the toaster. it

, provides the necessary compensation to prevent non-uniformity oftoasting during the heatingup period. In other words, the thermostaticelement 6i will take longer to heat from its cold condition when theentire toaster is cold than it will after the heating-up period hastaken place and, as a result, the toasting of the first slice of breadwill be of the necessary long duration to toast such slice to thedesired degree.

As previously indicated, the degree of toasting may be varied byadjusting the position of the heater element 65 through the manualrotation of knob 6. The effect of this is to vary the position of theheater element with respect to the thermostatic strip 6! and therebyvary the heat ing period of the cyclic operation above described.Obviously, the variation of the heating period varies the over-alltiming period of the mechanism and gives difierent degrees of toastingof the bread slices.

Broadly speaking, the illustrated toaster is representative of anyelectrical device whose operation it is desired to control; and the,switch 22-23, the latching means, and the latch-tripping member 3| arebroadly representative of a means for interrupting the operation of anysuch device. Therefore, the invention, in its broad aspect, provides anovel mechanism for controlling any electrical device.

It will also be apparent that the invention is not limited to thespecific structural details of the embodiment illustrated and describedbut is capable of various modifications while retaining the generalprinciples of operation. Therefore, it will be understood that theinvention is not limited by the present disclosure but only by the scopeof the appended claims.

We claim:

1. A timing mechanism comprising a movable member whose movement in onedirection eflects a timing operation, means for actuating said member insaid direction, a pivoted thermal-responsive element, meansinterconnecting said element with said member so as to rock said elementback and forth about its pivot during the movement of said member, afirst stop constructed and arranged to detain said element in oneposition when the element is cold, a second stop constructed andarranged to detain said elementin another position when the element isheated, and heating means continuously energized during the timingoperation and positioned so as to affect said element only when thelatter is in said one position, whereby the rocking motion of saidelement is controlledso as to control the movement of said memberaccordingly.

2. A timing mechanism comprising a movable member whose movement effectsa timing operation, means for actuating said member, a pivotedthermal-responsive element, rotatable means operatively connected tosaid member, means operable by said rotatable means to rock said elementback and forth about its pivot during the movement of said member, afirst stop constructed and arranged to detain said element in oneposition when the element is cold, a second stop constructed andarranged to detain said element in another position when the element isheated, and heating means positioned so as to be adjacent said elementwhen the latter is in said one position, whereby the rocking motion ofsaid element is controlled so as to control the movement of said memberaccordingly.

3. A timing mechanism comprising a movable member whose movement effectsa timing operation, means for actuating said member, a pivotedthermal-responsive element. means for rocking said element back andforth about its pivot during the movement of said member, a first stopconstructed and arranged to detain said element in one position when theelement is cold, a second stop constructed and arranged to-detain saidelement in another position when the element is heated, heating meanspositioned so as to be adjacent said element when the latter is in saidone position, whereby the rocking motion of said element is controlledso as to control the movement of said member accordingly, and means foradjusting the position of said heating means to thereby vary the periodof heating said element.

4. A timing mechanism comprising a movable member whose movement in onedirection through a predetermined range determines the length of atiming cycle, spring means for urging said member .in said direction,manually-operable means for moving said member in the opposite directionto initiate a timing cycle, a pivoted thermal-responsive element,rotatable means operatively connected to said member during thefirst-mentioned movement thereof, means operable by said rotatable meansto rock said element back and forth about its pivot, a first stopconstructed and arranged to detain said element in one position when theelement is cold, heating means at said position, means for energizingsaid heating means when a timing cycle is initiated, a second stopconstructed and arranged to detain said element in another position whenthe element is heated, and mean for deenergizing said heating means atthe end of a timing cycle.

EMIL WALDER. JOSEPH W. MYERS.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,576,649 Gregory Mar. 6, 19261,595,169 Schieferstein Aug. 10, 1926 1,795,013 Denman Mar. 3, 19312,036,178 Lucia Mar. 31, 1936 2,196,393 Ireland Apr, 9, 1940 2,221,863Crane Nov. 19, 1940 2,250,979 Winbome July 29, 1941 2,332,171 SardesonOch-19, 1943 2,422,199 Koci June 17, 1947 FOREIGN PATENTS Number CountryDate 335,946 France Dec. 22, 1903

